218 HALORAGE.E. CALLITRICHE. 



stamen with large thick filament and rather large 2-celled anther : fruit 

 oval or somewhat 4-sided, 2-3 lines long ; stigma persistent. In ponds and 

 marshes, Alaska to California, the Eastern States and Europe. 



Var. fluviatilis Hart. Larger; leaves 2-3 inches long, grass-like, in 

 closely crowded whorls Oregon to Canada and Sweden. 



H. tetraphyllum L. f Suppl. 81. Stems 10-12 inches high, leaves in 

 whorls of 4 or 6, oval to obovate, often feather-veined ; fruit less than 2 

 lines long. Alaska, perhaps northern Washington. 



H. montaiia Ledeb. Reichenb. Incon. Bot. i, 71. Stems 2-4 inches high; 

 leaves 1-nerved, linear mucronate, in whorls of 5-6, 4-6 lines long : flowers 

 often monoecious : fruit almost oval, a line or more long, minutely granu- 

 late. In wet turfy places, Alaska to Washington. 



2 CALLITRICHE L. Gen. n. 13. 



Small, mostly aquatic, herbs with opposite entire leaves with- 

 out stipules and small axillary monoecious flow r ers without pet- 

 als. Calyx adherent to the ovary the limb very short or obso- 

 lete. Petals none. Stamen one with slender filament and cor- 

 date 4-celled anther. Ovary 4-celled, with 2 filiform styles. 

 Fruit 4-celled, flattened and emargmate, 4-seeded, indehiscent, 

 the cells separating at maturity into 1 -seeded nutlets. 



* Emersed leaves obovate-spatulate, 3-nerved, the submersed 

 linear, (all uniform and narrow in terrestrial forms) : carpels connate. 



<- Fruit pedicillate, wing-margined; bract 3 none 



C. marginata Torr Pacif R. Rep. iv, 135." Stems slender, branch- 

 ing, rooting in the mud growing in water : submersed leaves linear, 1- 

 nerved, running gradually into the emersed oblanceolate or spatulate 3- 

 nerved ones, or the terrestrial form with linear spatulate 3-nerved leaves 

 4-5 lines long : peduncles about two-thirds as long as the leaves, spread- 

 ing or reflexed : styles as long or shorter than the fruit reflexed deciduous : 

 fruit broader than long with conspicuous membranaceous wings and di- 

 vergent lobes. From Arizona and California to The Dalles, Oregon. 



C. sepulta Watson Proc. Am. Acad. xiv, 298. Terrestrial, prostrate 

 and rooting in the mud: the numerous narrowly linear leaves 2-3 lines 

 long: fruit broader than long emarginate at both ends, the thick carpels 

 with acute divergent margins, on stout pedicels 1-3 lines long soon de- 

 flexed and buried in the soil : stigmas elongated, reflexed, soon deciduous. 

 Oregon. (Hall 1871.} 



C. verna L. Sp. i, 2. Perennial, with elongated stems and floating 

 rosulate obovate often emarginate leaves which are more .or less narrowly 

 petioled the submerged ones from spatulate to linear: sometimes terres- 

 trial and rooting with short linear leaves : bracts often longer than the 

 fruit rarely wanting: stigmas erect or spreading, usually shorter than the 

 fruit, deciduous: fruit oblong flat on the face mostly with a small apical 

 notch and narrow apical wings the grooves between the lobes deep. Com- 

 mon from Alaska to California, the Eastern States and Europe, Asia and 

 S. America. 



C. heterophylla Pursh. Perennial with elongated stems and obovate 

 floating leaves, the submerged ones linear -lanceolate, long acuminate, 

 4-8 lines long, sometimes terrestrial and rooting, with short linear leaves : 

 stigmas longer than the fruit persistent : fruit obovate, broader than long, 

 with a deep broad notch at the apex, thick, almost ventricose near the 

 base, the lobes obtusely angled, with a small groove between them, wing- 



